Polyadducts produced from nonlinear-optically active copolymers and polymerizable nonlinear-optically active monomers

ABSTRACT

The present invention relates to nonlinear-optically active copolymers which are composed of a chromophore acrylate, a glycidyl-functional acrylate, and a further acrylate unit, and to polyadducts produced from them by crosslinking with a carboxyl-functional polyester. The nonlinear-optical copolymers of the present invention, and the polyadducts prepared from them, possess an orientation stability in the crosslinked state, and a thermal stability, which makes them highly suitable for producing electrooptical and photonic components.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of U.S. application No. 09/265,444, filed Mar. 9,1999, now U.S. Pat. No. 6,174,961.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to polyadducts produced from nonlinear-opticallyactive copolymers and polymerizable nonlinear-optically active monomers,i.e., for electrooptical and photonic components.

Electrooptical and photonic components are important elements innonlinear optics and in optical information technology. They are planarwaveguide structures whose function can be altered by an electricalvoltage. They comprise modulators, Mach-Zehnder modulators, tunable andswitchable directional couplers, wavelength filters, including tunablewavelength filters, and polarization-modifying waveguide components.Their construction is described, for example, by R. C. Alferness in T.Tamir “Guided-Wave Optoelectronics”, Springer-Verlag Berlin, Heidelberg1988, pages 145 to 210, and in K. J. Ebeling “IntegrierteOptoelektronik”, 1st edition, Springer-Verlag Berlin, Heidelberg 1989,pages 152 to 162.

Components of this kind can be produced using highly anisotropicinorganic crystals which have a high 2nd-order susceptibility.

In the past, organic materials and polymers having high 2nd-ordersusceptibilities have also been developed. They feature considerableadvantages in terms of their preparation and their use in electroopticaland photonic components. Polymers having nonlinear-optical (NLO)properties are known from the literature; in this context see, forexample: S. R. Marder, J. E. Sohn, G. D. Stucky “Materials for NonlinearOptics”, ACS Symposium Series, Vol. 455 (1991), pages 128 to 156, R. A.Norwood et al. in L. A. Hornak “Polymers for Lightwave and IntegratedOptics”, Marcel Dekker, Inc., New York 1992, pages 287 to 320, and G. J.Ashwell, D. Bloor “Organic Materials for Nonlinear Optics”, RoyalSociety of Chemistry, Cambridge 1993, pages 139 to 155 and 332 to 343.

An overview of current problems in the development of materials havingpronounced NLO properties was recently published by T. J. Marks and M.A. Ratner in Angew. Chem. 107 (1995), pages 167 to 187. In addition tothe requirements that have to be set for nonlinear-optical chromophores,reference is also made to the problems in developing polymeric matricesfor the embedding or binding of chromophores, and theirorientation-stable alignment.

In order for such polymers, which are provided with covalently bonded ordissolved NLO chromophores, become nonlinear-optically active and have ahigh 2nd-order susceptibility, the chromophores must be oriented in anelectrical field (in this respect, see: J. D. Swalen et al. in J.Messier, F. Kajzar, P. Prasad “Organic Molecules for Nonlinear Opticsand Photonics”, Kluwer Academic Publishers 1991, pages 433 to 445). Thisnormally takes place in the region of the glass transition temperature,where the mobility of the chain segments of the polymers allowsorientation of the NLO chromophores. The orientation obtained in thefield is then frozen in by cooling. The 2nd-order susceptibility χ⁽²⁾that is achievable here is proportional to the spatial density of thehyperpolarizability β, to the ground-state dipole moment μ_(o) of thechromophores, to the electrical poling field, and to parameters whichdescribe the distribution of orientation following the poling process(in this respect, see: K. D. Singer et al. in P. N. Prasad, D. R. Ulrich“Nonlinear Optical and Electroactive Polymers”, Plenum Press, New York1988, pages 189 to 204).

Great interest attaches to compounds combining high dipole moment withhigh values of β. Consequently, investigation has focused in particularon those chromophores which consist of conjugated π electron systemsthat carry an electron donor at one end and an electron acceptor at theother end and are covalently bonded to a polymer: for example, topolymethyl methacrylate (U.S. Pat. No. 4,915,491), polyurethane (EP-A 0350 112), or polysiloxane (U.S. Pat. No. 4,796,976).

One particular problem of said polymer materials having NLO propertiesis the relaxation of the oriented chromophore units and thus the loss ofNLO activity. At present, this relaxation is still preventing theproduction of electrooptical components with long-term stability thatare deployable technically.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to providenonlinear-optically active copolymers and polyadducts produced from themby means of which post-orientation relaxation of the nonlinear-opticallyactive units in the NLO polymers is prevented or at least retarded.Moreover, the nonlinear-optically active polymers should exhibit lowoptical losses. The aim of the present invention is in particular toprovide NLO polymers with which relaxation of the chromophores isprevented up to temperatures of above 100° C. and which comprise thosenonlinear-optical units which ensure thermal stability at temperaturesof more than 200° C. In addition to this, the NLO polymers should allowextremely wide variation of the optical properties of the electroopticaland photonic components.

In order to achieve this object the present invention providesnonlinear-optically active copolymers of the general formula 1

in which R¹, R², R³, X¹, X², X³, Y¹, Y², Y³, Z, l, m and n are asdefined below. These are, therefore, nonlinear-optical,glycidyl-functional copolymers which in accordance with the inventioncan be reacted by crosslinking with a carboxyl-functional polyesterhaving an appropriate degree of polymerization, to give the polyadductsthat are likewise of the present invention.

The use of polyadducts based on glycidyl-functional nonlinear-opticallyactive copolymers is known per se. DE-A 196 39 381 proposes a materialfor which a polymer comprising a nonlinear-optical group and glycidylgroups is crosslinked by coreaction with cyanates or prepolymers inorder to achieve a stable orientation of the chromophore units. However,it has been found that the resulting material possesses only a lowfilm-forming tendency, and low thermal stability under polingconditions.

Surprisingly, it has been possible to eliminate these is disadvantagesby virtue of the nonlinear-optically active copolymers of the generalformula 1 of the present invention and, respectively, by the polyadductsobtained from them by crosslinking with a carboxyl-functional polyester.

The nonlinear-optical polyadducts of the present invention are preparedby crosslinking a nonlinear-optically active copolymer of the generalformula 1 having a proportion from 5 to 95 mol % of glycidyl groups,preferably from 20 to 80 mol %, and having a proportion of from 5 to 95mol %, preferably from 20 to 80 mol %, of simple linear or branched andalso cyclic esters, preferably of the cyclohexyl series, with at leastone carboxyl-functional polyester. Advantageously, there are from 0.1 to5 gram equivalents of the polyester component, based on the number ofcarboxyl groups employed, preferably from 0.4 to 2.7 gram equivalents,per gram equivalent of glycidyl groups of the NLO copolymer. As a resultof the coreaction of the glycidyl groups of the NLO copolymer and thepolyester component, tightly crosslinked polymer layers are produced inthe polymer film.

In the production of the electrooptical or photonic components, theabove-mentioned orientation and crosslinking take place on a support,where the crosslinked polyadduct forms the functional layer which isarranged between two buffer layers. With advantage, one or both bufferlayers of the electrooptical or photonic components according to theinvention can also consist, like the functional layer, of an appropriatecrosslinked NLO polymer. It is known that in that case the refractiveindex of the buffer layers is somewhat lower than that of the functionallayer. The required difference in refractive index (from thelight-guiding functional layer or from its waveguide structure) isestablished by means of an appropriate composition of the copolymerswith and without nonlinear-optical units.

The nonlinear-optically active, glycidyl-functional copolymers arepreferably compounds of the general formula 1:

In this formula:

R¹, R², R³ are identical or different from one another and are H, CH₃ orhalogen;

X¹, X², X³ are identical or different from one another and are O or NR⁴,where R⁴ is H or a linear or branched C₁₋ to C₆₋ -alkyl radical;

Y¹ is a linear or branched hydrocarbon chain having 2 to 20 carbonatoms, where one or more nonadjacent CH₂ groups, with the exception ofthe CH₂ group providing the link to the radical Z, can be replaced by O,S or NR⁵, where R⁵ is H or a linear or branched C₁₋ to C₆₋ alkylradical;

Y² is a linear or branched hydrocarbon chain having 1 to 3 carbon atoms;

Y³ is a linear or branched C₁₋ to C₂₀₋ alkyl radical, a C₅₋ to C₇₋cycloalkyl radical or a bi- or tricyclic alkyl radical having up to 18carbon atoms;

Z is a nonlinear-optically active group; and

l:m:n=1 . . . 99:1 . . . 99:1 . . . 99.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferably, in the copolymer of formula 1:

R¹=R²=R³=CH₃,

X¹=X²=X³=O,

Y¹=(CH₂)_(o), where o=2 to 6,

Y²=CH₂,

Y³=cyclohexyl, norbornyl, adamantyl or methyl, and

l:m:n=10 . . . 50:10 . . . 30:20 . . . 80.

The radicals R⁴ and R⁵, which can be the same or different, are inparticular a methyl, ethyl, propyl, isopropyl, butyl, isobutyl,sec-butyl, pentyl, isopentyl, neopentyl, hexyl or 2-methylpentylradical.

The nonlinear-optically active group Z can, for example, be achromophore of the azo dye, stilbene dye, or polymethine dye type.Preferably, the group Z has a structure of the general formula 2:

which is attached by D to Y¹ and where

D is O, S or NR⁹ where R⁹ is a hydrogen atom, a linear or branched C₁₋to C₂₀₋ alkyl radical which is uninterrupted or interrupted by 1 to 5oxygen atoms in ether function, or is a benzyl radical or a phenyl ornaphthyl radical, or R⁹ and Y¹ together with the nitrogen atomconnecting them, form a pyrrolidinyl, piperidinyl, morpholinyl orpiperazinyl radical,

R⁶, R⁷, R⁸ are independently of one another a hydrogen atom, a linear orbranched C₁₋ to C₂₀₋ alkyl radical which is uninterrupted or interruptedby 1 to 5 oxygen atoms in ether function or are a phenyl, naphthyl,thienyl, thiazolyl or pyridyl radical,

Q is an electron-acceptor-substituted methylene or imino group,

A is S, O. NR¹⁰ or a ring double bond, or is

where R¹⁰ is a hydrogen atom, a linear or branched C₁₋ to C₂₀₋ alkylradical or a phenyl or naphthyl radical and T is CH or N or, if desired,Q and T together form a structure of the type ═N—SO₂—C≡, ═N—CS—C≡ or═N—CO—C≡, and

B is a CH or CR¹¹ group or is N, where R¹¹ is a linear or branched C₁₋to C₂₀₋ alkyl radical, a phenyl radical or a naphthyl radical.

The radicals R⁶ to R¹¹ can in particular be a methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, pentyl, isopentyl, neopentyl,tert-pentyl, hexyl, 2-methyl-pentyl, heptyl, octyl, 2-ethylhexyl,isooctyl, isononyl, decyl or isodecyl radical, and also thecorresponding alkoxy or alkenyl radicals (the terms isooctyl, isononyland isodecyl in this list are trivial names derived from the alcoholsobtained in an oxo synthesis; in this respect, see: “Ullmann'sEncyclopedia of Industrial Chemistry”, 5th Edition, Vol. A1, pages 290to 293, and Vol. A10, pages 284 and 285).

With particular preference, R⁶, R⁷ and R⁸ are each a nitrogen atom, A isa sulfur atom or a 1,2-fused benzene ring, B is a CH group, and Q is adicyanomethylene group. Furthermore, Q and T together preferably form astructure ═N—SO₂—C≡. Q can, moreover, be analkoxycarbonylcyanomethylene, cyanoimino or alkoxycarbonylimino group. Dis preferably a substituted amino radical.

Compounds of the general formula 2 are described in detail in thesimultaneously filed German Patent Application 198 10 030.2(“Chromophoric compounds and process for their preparation”).

Z can also be an azamethine of the following structure 2B:

which is linked to Y¹ through R¹² and where

R¹² and R¹³ are identical or different from one another and are in eachcase a linear or branched C₁₋ to C₂₀₋ alkyl radical which can beinterrupted by up to five ether oxygen atoms, a phenyl, naphthyl,thienyl, thiazolyl or pyridyl radical or R¹² and R¹³ together form afive- or six-membered carbocyclic or heterocyclic ring;

R¹⁴ is a hydrogen atom, a hydroxyl or acyloxy group, a linear orbranched C₁₋ to C₂₀₋ alkyl radical or a phenyl radical which isoptionally substituted in the para position by a halogen, hydroxyl oracyloxy group;

G denotes S, Se, O or NR⁴, where R⁴ is a hydrogen atom or a linear orbranched C₁₋ to C₂₀₋ alkyl radical, or denotes a ring double bond or a1,2-fused benzene ring;

E denotes a CH or CR⁵ group, where R⁵ is a linear or branched C₁₋ toC₂₀₋ alkyl radical, a phenyl or a naphthyl radical, or denotes N; and

M denotes S, Se, O or NR⁶, where R⁶ is a hydrogen atom or a linear orbranched C₁₋ to C₂₀₋ alkyl radical, or denotes a ring double bond or a1,2-fused benzene ring;

T and L are identical or different from one another and each denotes aCH or CR⁷ group, where R⁷ is a C₁₋ to C₂₀₋ alkyl radical, an optionallysubstituted phenyl or a naphthyl radical, or denotes N, or T and Ltogether denote a ring double bond or a 1,2-fused benzene ring, with theproviso that when G is a ring double bond, T and L together and M arenot simultaneously a ring double bond and a 1,2-fused benzene ring; and

Acc is a nitrile, C₁₋ to C₂₀₋ alkoxycarbonyl, formyl, acyl, arylsulfonylor nitro group.

Compounds of this kind are described in detail in the simultaneouslyfiled German Patent Application 198 10 063.9 (“Process for preparingazamethines, and azamethines themselves”).

The nonlinear-optically active copolymers are amorphous copolymerscomprising comonomers which have covalently bonded nonlinear-opticalmolecule units and comonomers with crosslinking-active functionalgroups. The preparation of the copolymers by free-radical polymerizationand the synthesis of the precursors take place either in accordance withthe conventional processes and/or are described in the working examples.

The free-radical polymerization is able to take place by means offree-radical initiators which decompose on heating. Initiators of thiskind which are used are preferably azoisobutyronitrile and peroxycompounds, such as dibenzoyl peroxide.

The role of crosslinking-active component in the present invention isplayed by a carboxyl-functional polyester of the general formula 3:

In this formula, p denotes values between 10 and 350, preferably between100 and 150. These values represent degrees of polymerization which aresuitable in the context of the present invention. The polyesters areeither commercially available or can be produced by correspondingpolymerization of a suitably substituted isophthalic acid ester.

To improve the surface quality, the processability and/or thecompatibility with polymers it is possible to add processing auxiliariesto the polyadducts of the invention, depending on the intendedapplication. Examples of these auxiliaries are thixotropic agents,flow-control agents, plasticizers, wetting agents, lubricants, andbinders.

The polyadducts according to the invention are applied in dissolved orliquid form, together if desired with crosslinking-active compounds orinitiators, to a substrate by spin coating, dipping, printing orbrushing. In this way a nonlinear-optical arrangement is obtained inwhich the polyadducts or corresponding prepolymers—before or duringcrosslinking—are given a polar alignment in electrical fields. Aftercooling, polymer materials having excellent nonlinear-optical propertiesand—by virtue of the crosslinking—increased orientation stability andthus increased long-term stability, even at relatively high servicetemperatures, are obtained.

In order to produce the nonlinear-optical materials it is particularlyadvantageous to use oligomeric prepolymers of the adducts of theinvention. These prepolymers are prepared conventionally, with thecopolymers comprising nonlinear-optically active glycidyl groups andsimple linear, branched or cyclic esters being reacted with an excess ofthe carboxyl-functional polyester compound. Following application to asubstrate, the prepolymers undergo polar alignment—at a temperatureabove the glass transition temperature—and are subsequently crosslinkedin an applied electrical field to give the nonlinear-optical polyadductshaving an improved profile of properties.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin nonlinear-optically active copolymers, polyadducts produced fromthem, and their use for nonlinear-optical media, it is nevertheless notintended to be limited to the details shown, since various modificationsand structural changes may be made therein without departing from thespirit of the invention and within the scope and range of equivalents ofthe claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments.

The working examples which follow are intended to illustrate theinvention, and describe the synthesis of novel nonlinear-opticallyactive compounds (Examples 1 to 6) and of glycidyl-functionalnonlinear-optically active copolymers (Example 7), of a polyestercrosslinker (Example 8), and of polyadducts (Example 9) and theircrosslinking (Example 10), and electrooptical investigations (Example11).

The following abbreviations are used in the examples:

m.p.=melting point;

b.p.=boiling point;

yld.=yield;

decomp.=decomposition.

EXAMPLE 1 Methacrylate of benzo[a]-5-dicyanomethylene-9-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine

a) 0.11 mol of n-butyl bromide and 0.1 mol of NaHCO₃ are added to 0.1mol of m-aminophenol in 150 ml of methanol and the mixture is refluxedfor 5 h. After cooling, the mixture is filtered and the solvent isremoved in vacuo. The oil which remains is fractionated in vacuo, togive 3-(n-butyl-amino)phenol in a yield of 57%; b.p. 110° C. (6·10⁻⁵torr), m.p. 35° C.

b) 0.1 mol of 3-(n-butyl-amino)phenol in 100 ml of methanol is refluxedfor 10 h with 0.11 mol of 2-bromoethanol and 0.1 mol of NaHCO₃. Aftercooling, the mixture is filtered, the solvent is removed in vacuo andthe residue is fractionated, to give3-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-phenol in a yield of 54%; b.p.130-140° C. (5·10⁻⁵ torr), m.p. 45-47° C.

c) 0.05 mol of compound of b) is dissolved in 50 ml of HCl-saturatedpropanol and 0.1 mol of isoamyl nitrite is added. After 20 minutes, 150ml of diethyl ether are added and the product formed is filtered offwith suction, to giveN-(n-butyl)-N-(2-hydroxyethyl)-N′-hydroxyquinone-diiminium chloride in ayield of 76%; m.p. 127° C. (decomp.).

d) 0.01 mol of the compound of c) is heated briefly at boiling with0.011 mol of 1-naphthylmalononitrile and 0.02 mol of triethylamine in 15ml of dimethylformamide. After cooling, water is added and the productwhich precipitates is extracted with dichloroethane. Followingdistillative removal of the solvent, the residue is purified by repeatedchromatography over silica gel, using ethyl acetate as eluent, to give9-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-5-dicyanomethylenebenzo[a]-phenoxazine,a compound of the following structure:

Yld. 30%, m.p. 190° C., λ_(max): 618 nm (in toluene).

e) 0.005 mol of the dye of d) is heated over a water bath for 1 h with0.005 mol of methacryloyl chloride and 0.005 mol of triethylamine in 100ml of tetrahydrofuran. The mixture is subsequently evaporated to drynessand the residue is taken up in dichloromethane. Following removal of thesolvent, the residue is purified over silica gel using ethyl acetate aseluent, to give the title compound; m.p. 115° C., yld. 53%.

EXAMPLE 2 Methacrylate ofbenzo[a]-5-dicyanomethylene-9-[N-(n-heptyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine

a) 0.11 mol of n-heptyl bromide and 0.1 mol of NaHCO₃ are added to 0.1mol of m-aminophenol in 150 ml of methanol and the mixture is refluxedfor 5 h. After cooling, the mixture is filtered and the solvent isremoved in vacuo. The oil which remains is fractionated in vacuo, togive 3-(n-heptyl-amino)phenol; b.p. 130-140° C. (8·10⁻⁵ torr), m.p.27-30° C., yld. 62%.

b) 0.1 mol of 3-(n-heptyl-amino)phenol in 100 ml of methanol is refluxedfor 10 h with 0.11 mol of 2-bromoethanol and 0.1 mol of NaHCO₃. Aftercooling, the mixture is filtered, the solvent is removed in vacuo andthe residue is fractionated, to give3-[N-(n-heptyl)-N-(2-hydroxyethyl)amino]phenol; b.p. 160-170° C. (1·10−5 torr), m.p. 45-47° C., yld. 54%.

c) 0.05 mol of the compound of b) is dissolved in 50 ml of HCl-saturatedpropanol, and 0.1 mol of isoamyl nitrite is added. After 20 minutes, 150ml of diethyl ether are added and the product which forms is filteredoff with suction, to giveN-(n-heptyl)-N-(2-hydroxyethyl)-N′-hydroxyquinone-diiminium chloride;m.p. 129° C. (decomp.), yld. 62%.

d) 0.01 mol of the compound of c) is heated briefly at boiling with0.011 mol of 1-naphthylmalononitrile and 0.02 mol of triethylamine in 15ml of dimethylformamide. After cooling, water is added and the productwhich precipitates is extracted with dichloroethane. Followingdistillative removal of the solvent, the residue is purified by repeatedchromatography over silica gel, using ethyl acetate as eluent, to give9-[N-(n-heptyl)-N-(2-hydroxyethyl)amino]-5-dicyanomethylenebenzo-[a]phenoxazine,a compound of the following structure:

Yld. 28%, m.p. 155-157° C., λ _(max): 622 nm (in toluene)

e) 0.005 ml of the dye of d) is reacted with 0.005 mol of methacryloylchloride and 0.005 mol of triethylamine as in Example 1e to give themethacrylate of the dye, i.e., the title compound; m.p. 103-105° C.,yld. 65%.

EXAMPLE 3 Methacrylate of2-dicyanomethylene-6-[N-(n-butyl)-N-(2-hydroxyethyl)amino]thieno[3,2-b]benzo[e]oxazine

a) In analogy to Example 1,2-dicyanomethylene-6-[N-(n-butyl)-N-(2-hydroxyethyl)amino]thieno[3,2-b]-benzo[e]oxazineof the formula

is prepared by refluxing 0.01 mol ofN-(n-butyl)-N-(2-hydroxyethyl)-N′-hydroxyquinone-diiminium chloride (seeExample 1c) with 0.01 mol of 2-thienylmalononitrile, which was preparedby reacting 0.13 mol of malononitrile in 100 ml of absolutetetrahydrofuran with 0.15 mol of sodium hydride, 0.0015 mol of[(C₆H₅)₃P]₂PdCl₂ and 25 g of 2-iodothiophene by boiling for 3 hoursunder reflux followed by neutralization with hydrochloric acid, in ayield of 45%, in 15 ml of dimethylformamide to which 0.02 mol oftriethylamine was added, for several minutes. After cooling, theresultant solution is diluted with water and the dye precipitated in thecourse of dilution is isolated by filtration with suction. It ispurified by repeated column chromatography over silica gel using ethylacetate as eluent; yld. 23%, m.p. 260° C.

b) The dye is converted into the methacrylate—in accordance with Example1—by reaction with methacryloyl chloride in the presence oftriethylamine.

EXAMPLE 4 Methacrylate of9-[N-(n-heptyl)-N-(2-hydroxyethyl)-amino]benzo[d]isothiazolo[3,3a,4-ab]phen-7,12-oxazine4-dioxide

In analogy to Example 2,N-(n-heptyl)-N-(2-hydroxyethyl)-N′-hydroxyquinone-diiminium chloride(see Example 2c) and 1,8-naphthosultam are used to prepare a phenoxazinedye of the following structure (m.p. 178-180° C., yld. 35%):

By reaction with methacryloyl chloride in tetrahydrofuran to whichfreshly distilled triethylamine has been added, the dye is convertedinto the methacrylate of the following structure:

EXAMPLE 5 Benzo [a]-5-cyanoimino-9-[N-(n-butyl)-N-(2-hydroxy-ethyl)-amino]-7,12-phenoxazine

In analogy to Example 1,N-(n-butyl)-N-(2-hydroxy-ethyl)-N′-hydroxyquinone-diiminium chloride(see Example 1c) and N-cyano-1-naphthylamine are used to prepare aphenoxazine dye of the following structure (m.p. 173-175° C., yld. 25%):

By reaction with methacryloyl chloride in tetrahydrofuran to whichfreshly distilled triethylamine has been added, the dye is subsequentlyconverted into the methacrylate of the following structure:

EXAMPLE 6Pyridino[2,3-a]-5-cyanoimino-9-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine

In analogy to Example 1,N-(n-butyl)-N-(2-hydroxyethyl)-N′-hydroxyquinone-diiminium chloride (seeExample 1c) and 8-cyanoaminoquinoline are used to prepare a phenoxazinedye of the following structure (m.p. 185-187° C., yld. 32%):

By reaction with methacryloyl chloride in tetrahydrofuran to whichfreshly distilled triethylamine has been added, the dye is subsequentlyconverted into the methacrylate of the following structure:

EXAMPLE 7 Synthesis of Glycidyl-functional Nonlinear-optically ActiveCopolymers

For the copolymerization of 1 moles of nonlinear-optically activechromophore methacrylates—for example, of the oxazine dyes in accordancewith Example 2 (P2a to P2c)—with m moles of glycidyl methacrylate and nmoles of cyclohexyl methacrylate the three components together with 2mol % of azoisobutyronitrile are reacted in oxygen-free absolutechlorobenzene (90% by mass, based on the amount of dye) under argon in aSchlenk tube at 75° C.; the reaction period is from 18 to 24 hours. Thecrude product of this reaction is dissolved completely by addingtetrahydrofuran and is precipitated from methanol. In order to purifythe copolymer, it is reprecipitated a number of times. The resultsobtained in this procedure are summarized in Table 1 (T_(G)=glasstransition temperature).

TABLE 1 Composition Polymer No. 1:m:n mol % % Yield T_(g) ° C. P2a33:15:52 87 133 P2b 25:15:60 85 127 P2c 20:15:65 92 118

EXAMPLE 8 Synthesis of a Polyester Crosslinker

5-Acetoxyisophthalic acid is refluxed in glacial acetic acid until thedesired degree of polymerization is attained; thereafter, the resultingpolyester is precipitated by dropwise introduction into water. Themolecular weight distribution is determined by gel permeationchromatography.

EXAMPLE 9 Synthesis of Polyadducts

2 parts by weight of the polyester prepolymer of Example 8 and 98 partsby weight of a glycidyl-functional nonlinear-optical copolymer inaccordance with Example 7 are dissolved homogeneously in cyclohexanoneat 20° C.; in the course of dissolution there is slight crosslinking.

EXAMPLE 10 Crosslinking of the Polyadducts

For crosslinking, the adducts of the polyester resin and of theglycidyl-functional nonlinear-optically active copolymer of Example 9are applied to suitable support materials, such as glass, ITO-coatedglass (ITO—indium-tin-oxide) or silicon wafers, by spin coating from asolution, preferably in cyclohexanone, and are freed from the solvent invacuo at elevated temperature, preferably at 70° C. for 15 hours.Subsequently, the substrate is provided with a covering electrode and isslowly heated in an electrical DC field to the glass transitiontemperature of the respective material; during this heating procedure,the material of the coating undergoes dipolar alignment and simultaneouscrosslinking.

The reaction conditions and the results obtained are summarized in Table2 (T_(G)=glass transition temperature)

TABLE 2 Polyadduct from Cure cycle and prepolymer temperature T_(g)after cure ° C. P1a *) 125° C., 1 h 145 P2a 135° C., 1 h 152 *) P1a =Chromophore methacrylate of Example 1 with a composition ratiocorresponding to prepolymer P2a.

EXAMPLE 11 Electrooptical Investigations

For the electrooptical investigations, films of the polyadducts of theinvention are produced with, customarily, is a film thickness of from 2to 6 μm. For the electrical poling, in order to achieve a highnoncentrosymmetrical orientation, a gold electrode is applied to thefilm (of the polyadduct) by sputtering; the counterelectrode is atransparent ITO layer. While the sample is being heated up to the regionof the glass transition temperature, a direct voltage is applied, withthe required increase in voltage being adjusted to the orientationbehavior of the nonlinear-optical molecule units, in order to avoidelectrical breakdown and thus destruction of the film. Once a polingfield strength of from 100 to 200 V/μm has been reached, a poling periodof about 30 minutes is sufficient to orient the nonlinear-opticalmolecule units. Thereafter, the sample is cooled—with a constantlyapplied field—to room temperature, thereby fixing the orientation.

The electrooptical investigations of the polymer samples are made byinterferometric measurement of a laser beam, beamed in obliquely,following single reflection at the gold electrode. The measurement setuprequired for this purpose, and the evaluation of the measurement, areknown (see, for example: Appl. Phys. Lett., Vol. 56 (1990), pages 1734to 1736).

Using the nonlinear-optically active copolymers and the polyadductsobtained by pre-crosslinking with a carboxyl-functional polyester,according to the invention, it is possible to produce, in a knownmanner, electrooptical and photonic components, in which thepolyadducts, as already mentioned, can be employed as functional layersand/or buffer layers.

We claim:
 1. A polyadduct which is formed from nonlinear-opticallyactive terpolymer of the general formula 1

R¹, R², R³ are identical or different from one another and are H, CH₃ orhalogen; X¹, X², X³ are identical or different from one another and areO or NR⁴, where R⁴ is H or a linear or branched C₁₋ to C₆₋ alkylradical; Y¹ is a linear or branched hydrocarbon chain having 2 to 20carbon atoms, where one or more nonadjacent CH₂ groups, with theexception of the CH₂ group providing the link to the radical Z, can bereplaced by O, S or NR⁵, where R⁵ is H or a linear or branched C₁₋ toC₆₋ alkyl radical; Y² is a linear or branched hydrocarbon chain having 1to 3 carbon atoms; Y³ is a linear or branched C₁₋ to C₂₀₋ alkyl radical,a C₅₋ to C₇₋ cycloalkyl radical or a bi- or tricyclic cycloaliphaticradical having up to 18 carbon atoms; Z is a nonlinear-optically activegroup; and l:m:n=1 . . . 99:1 . . . 99:1 . . . 99, and at least onecrosslinking agent based on a carboxyl-functional polyester.
 2. Thepolyadduct according to claim 1, in which the polyester is a5-hydroxyisophthalic ester of the general formula 3:

in which p is a value between 10 and
 350. 3. The polyadduct according toclaim 2 characterized in that p is a value between 100 and
 150. 4. Anonlinear-optical medium comprising a substrate, at least one functionallayer including a polyadduct according to claim 1, and at least onebuffer layer.
 5. The nonlinear-optical medium according to claim 4, inwhich the substrate is indium-tin oxide.
 6. The nonlinear-optical mediumaccording to claim 4, in which at least one buffer layer includes apolyadduct as claimed in claim
 1. 7. A polymerizable nonlinear-opticallyactive monomer represented by the formula CH₂═C(R¹)CO—X¹—Y¹—Z, in whichR¹ is H, CH₃ or halogen; X¹ is O or NR⁴, where R⁴ is H or a linear orbranched C₁₋ to C₆₋ alkyl radical; Y¹ is a linear or branchedhydrocarbon chain having 2 to 20 carbon atoms, where one or morenonadjacent CH₂ groups, with the exception of the CH₂ group providingthe link to the radical Z, can be replaced by O, S or NR⁵, where R⁵ is Hor a linear or branched C₁₋ to C₆₋ alkyl radical; and Z is anonlinear-optically active group of the general formula 2:

which is attached by D to Y¹ and where D is O, S or NR⁹ where R⁹ is ahydrogen atom, a linear or branched C₁₋ to C₂₀₋ alkyl radical which isuninterrupted or interrupted by 1 to 5 ether oxygen atoms, or is abenzyl radical or a phenyl or naphthyl radical, or R⁹ and Y¹ togetherwith the nitrogen atom connecting them, form a pyrrolidinyl,piperidinyl, morpholinyl or piperazinyl radical, R⁶, R⁷, R⁸ are each ahydrogen atom, a linear or branched C₁₋ to C₂₀₋ -alkyl radical which isuninterrupted or interrupted by 1 to 5 ether oxygen atoms or are aphenyl, naphthyl, thienyl, thiazolyl or pyridyl radical, Q is anelectron-acceptor-substituted methylene or imino group, A is S, O, NR¹⁰or a ring double bond, or is

where R¹⁰ is a hydrogen atom, a linear or branched C₁₋ to C₂₀₋ alkylradical or a phenyl or naphthyl radical and T is CH or N, or Q and Ttogether form a structure of the type ═N—SO₂—C≡, ═N—CS—C≡ or ═N—CO—C≡,and B is a CH or CR¹¹ group or is N, where R¹¹ is a linear or branchedC₁₋ to C₂₀₋ alkyl radical, a phenyl radical or a naphthyl radical. 8.The nonlinear-optically active polymerizable monomer according to claim7, in which R¹ is CH₃.
 9. The nonlinear-optically active polymerizablemonomer according to claim 7, in which X¹ is O.
 10. Thenonlinear-optically active polymerizable monomer according to claim 7,in which Y¹ is a C₂₋ to C₆₋ hydrocarbon chain.
 11. Thenonlinear-optically active polymerizable monomer according to claim 7,in which R⁶, R⁷ and R⁸ are each H.
 12. The nonlinear-optically activepolymerizable monomer according to claim 7, in which A is S or a1,2-fused benzene ring.
 13. The non-linear optically activepolymerizable monomer according to claim 7, in which B is a CH group.14. The nonlinear-optically active polymerizable monomer according toclaim 7, in which Q is a dicyanomethylene group or together with T formsa structure ═N—SO₂—C≡.
 15. The nonlinear-optically active polymerizablemonomer according to claim 7, in which Q is analkoxycarbonylcyanomethylene, cyanoimino or alkoxycarbonylimino group.16. The nonlinear-optically active polymerizable monomer according toclaim 7, which is methacrylate ofbenzo[a]-5-dicyanomethylene-9-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine.17. The nonlinear-optically active polymerizable monomer according toclaim 7, which is methacrylate ofbenzo[a]-5-dicyanomethylene-9-[N-(n-heptyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine.18. The nonlinear-optically active polymerizable monomer according toclaim 7, which is methacrylate of2-dicyanomethylene-6-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-thieno[3,2-b]benzo[e]oxazine.19. The nonlinear-optically polymerizable monomer according to claim 7,which is methacrylate of9-[N-(n-heptyl)-N-(2-hydroxyethyl)amino]-benzo[d]isothiazolo[3,3a,4-ab]-phen-7,12-oxazine-4-dioxide.20. The nonlinear-optically active polymerizable monomer according toclaim 7, which is methacrylate ofbenzo[a]-5-cyanoimino-9-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine.
 21. The nonlinear-optically activepolymerizable monomer according to claim 7, which is methacrylate ofpyridino[2,3-a]-5-cyanoimino-9-[N-(n-butyl)-N-(2-hydroxyethyl)amino]-7,12-phenoxazine.